1. Field of Disclosure
This disclosure relates generally to a post driver with grapple mechanism, and more particularly, to a grapple member on a post driver which is biased toward a generally horizontal position at rest, but which rotates into a generally vertical position suitable for post-driving when a post is grappled.
2. Background Art
Post drivers that utilize the pile driving principle of raising a weight to some distance above a post and then dropping the weight in order to drive the post rely heavily upon the skill of the operators to properly position the post and post driver in the correct position. Indeed, many post drivers require at least two operators—one to position the post and another to operate the skid-steer and the post driver itself. When a post is properly positioned within the post driver, the kinetic energy of the falling might is transferred into the post, pushing it into the ground. However, when a post is not properly positioned within the post driver, various issues may arise. The weight may fail to contact the post upon falling, and may instead impact upon the frame of the post driver (a dry fire), or the post may be extend too far into the post driver such that the overall driving performance of the driver is reduced due to a shorter stroke length. Additionally, the use of two operators creates inefficiencies and slowdowns, and puts the operator in charge of positioning the post in a position of some danger.
Hydraulic grapple mechanisms have been added to some existing devices to reduce the number of operators necessary to drive posts. Generally, such mechanisms include hydraulics for actuation of the grapple, as well as for swinging the grapple mechanism into and/or out of proper alignment with the post driver. Additionally, most such grapple mechanisms are located on the front of the housing of the post driver, creating two problems. First, when swinging from a horizontal to a vertical position, the post is angled directly at the operator in the skid-steer. If the post slips out of the grapple mechanism, it will fall toward the skid-steer and the operator. Second, this positioning puts the post driver in between the operator and the post, making it hard for the operator to see what is happening.